Loh Ping Yeap, Nakashima Hiroki, Muraki Satoshi
Department of Human Science, Graduate School of Design, Kyushu University, Fukuoka, Japan; Research Fellow of Japan Society for the Promotion of Science, Japan.
Department of Human Science, Graduate School of Design, Kyushu University , Fukuoka , Japan.
PeerJ. 2016 Sep 22;4:e2510. doi: 10.7717/peerj.2510. eCollection 2016.
The present study investigated the effects of grip on changes in the median nerve cross-sectional area (MNCSA) and median nerve diameter in the radial-ulnar direction (D1) and dorsal-palmar direction (D2) at three wrist angles. Twenty-nine healthy participants (19 men [mean age, 24.2 ± 1.6 years]; 10 women [mean age, 24.0 ± 1.6 years]) were recruited. The median nerve was examined at the proximal carpal tunnel region in three grip conditions, namely finger relaxation, unclenched fist, and clenched fist. Ultrasound examinations were performed in the neutral wrist position (0°), at 30°wrist flexion, and at 30°wrist extension for both wrists. The grip condition and wrist angle showed significant main effects (p < 0.01) on the changes in the MNCSA, D1, and D2. Furthermore, significant interactions (p < 0.01) were found between the grip condition and wrist angle for the MNCSA, D1, and D2. In the neutral wrist position (0°), significant reductions in the MNCSA, D1, and D2 were observed when finger relaxation changed to unclenched fist and clenched fist conditions. Clenched fist condition caused the highest deformations in the median nerve measurements (MNCSA, approximately -25%; D1, -13%; D2, -12%). The MNCSA was significantly lower at 30°wrist flexion and 30°wrist extension than in the neutral wrist position (0°) at unclenched fist and clenched fist conditions. Notably, clenched fist condition at 30°wrist flexion showed the highest reduction of the MNCSA (-29%). In addition, 30°wrist flexion resulted in a lower D1 at clenched fist condition. In contrast, 30°wrist extension resulted in a lower D2 at both unclenched fist and clenched fist conditions. Our results suggest that unclenched fist and clenched fist conditions cause reductions in the MNCSA, D1, and D2. More importantly, unclenched fist and clenched fist conditions at 30°wrist flexion and 30°wrist extension can lead to further deformation of the median nerve.
本研究调查了在三个腕关节角度下，握力对正中神经横截面积（MNCSA）以及正中神经在桡尺方向（D1）和背掌方向（D2）直径变化的影响。招募了29名健康参与者（19名男性[平均年龄，24.2±1.6岁]；10名女性[平均年龄，24.0±1.6岁]）。在三种握力条件下，即手指放松、半握拳和握拳时，对近端腕管区域的正中神经进行检查。对双腕在中立腕位（0°）、腕关节屈曲30°和腕关节伸展30°时进行超声检查。握力条件和腕关节角度对MNCSA、D1和D2的变化显示出显著的主效应（p<0.01）。此外，在MNCSA、D1和D2方面，握力条件和腕关节角度之间存在显著的交互作用（p<0.01）。在中立腕位（0°）时，当手指放松转变为半握拳和握拳状态时，观察到MNCSA、D1和D2显著减小。握拳状态导致正中神经测量值的变形最大（MNCSA，约-25%；D1，-13%；D2，-12%）。在半握拳和握拳状态下，腕关节屈曲30°和腕关节伸展30°时的MNCSA显著低于中立腕位（0°）时。值得注意的是，腕关节屈曲30°时的握拳状态下MNCSA减小最多（-29%）。此外，腕关节屈曲30°时在握拳状态下导致D1较低。相比之下，腕关节伸展30°时在半握拳和握拳状态下均导致D2较低。我们的结果表明，半握拳和握拳状态会导致MNCSA、D1和D2减小。更重要的是，腕关节屈曲30°和腕关节伸展30°时的半握拳和握拳状态会导致正中神经进一步变形。
